Rmx spring question

[03machstock]

So iv been working on the 89 rmx 250 i picked up a while back and its finally in reliable riding condition. Anyway, i did the fork seals 2 days ago figuring that they were soft because the previous owner had it sitting for so long that they leaked out all of the fluid(seals were bad and leaking). The one side didnt have much fluid in it but the other did so it was not as bad as i thought. I put 10 weight fork out in thinking it would stiffen it up a bit. Well its still too soft because im about 230 pounds and from what iv read is they were tuned for a 150 pound rider from the factory. I talked to the local suspension shop and they said they could sell me fork springs for my weight for about 100 bucks. My question is should i go for it, would it make a huge difference? Or should i seek out a more modern fork to swap onto the bike and then spring it for my weight? Im not a pro rider and might enter a hare scramble every now and then so unless it makes a huge difference probably wont be worth it to me, just looking for some input. Sorry for the long post and for that i give you some before and after pictures.....cant figure out how to uplod them in the new format so you'll have to go to photobucket link to see them

www.photobucket.com/rmxpics

[zig06]

100 dollars for fork springs seems reasonable, what about the shock spring?

I seem to think that the stock fork oil for that model was 10w, but no matter, adding a heavier oil isn't what you need. Go to Race Tech's web site, there you will find a "spring calculator". You might find that the damping is correct but the springs (forks and shock) might be too low for your weight.

In my honest opinion swapping out the forks (updating to a newer model) and the shock is a total waste of money. Keep it stock and dial it in for you, you'll be many dollars ahead. FWIW, if I had a good running RMX it'd Hare Scramble race it today, they are good bikes and if you didn't finish well it wouldn't be the bikes fault.

[03machstock]

Ok sounds good thanks. He said 150 to re spring and overhaul the rear, so 250 total (i would do the front springs myself as its too simple to paysomeone) for a suspension set up for my weight. I went and rode the thing for the first time longer than 10 minutes yesterday and i love the bike, just needs some suspension work and i think i might go up 1 tooth to 51 on the rear. Anyway, thanks for the help,

Dan

[rob223]

i have a 94 rmx and doing my suspention was the best thing i did,i'm 240 so it needed it

[03machstock]

Thanks zig and rob, exactly what i was looking for.

Dan

[03machstock]

Just got back from my local suspension shop and dropped off my rear shock to be serviced and resprung, however on the front i am pretty screwed. The only people that made aftermarket springs for my stock 41mm forks made a .47 kg spring rate, and it is obsolete. No one has one anywhere that i can find. Anybody have any ideas?

[Team Roost]

Just got back from my local suspension shop and dropped off my rear shock to be serviced and resprung, however on the front i am pretty screwed. The only people that made aftermarket springs for my stock 41mm forks made a .47 kg spring rate, and it is obsolete. No one has one anywhere that i can find. Anybody have any ideas?

http://racetech.com/

I just resprung my 96 RMX front and rear with Eibach springs I got from racetech.

If you order from them, use promo code "realmotocross 2012" for 20% off. Can't beat that deal..

[03machstock]

Racetech was the manufacturer that carried the .47kg Eibach springs that are now obsolete. Sorry I should have included that.

[Team Roost]

You will need to go up to the next closest size (.48 kg), thats what I had to do. Give them a call and they will help you figure out what will work for you.

[tribalbc]

If you can't find any springs you could add some preload with a spacer to your existing springs.

[03machstock]

You will need to go up to the next closest size (.48 kg), thats what I had to do. Give them a call and they will help you figure out what will work for you.

No, they DO NOT make springs for this anymore. .48 is optimal for my weight. They used to make a .47 but it is obsolete and that was my closest option. If i could just get any brand springs close i would do that. I have already called racetech and they said im pretty much screwed.

If you can't find any springs you could add some preload with a spacer to your existing springs.

Ah ok, now how much preload could i add before bottoming out. Correct me if im wrong but the spring bottoms out before the fork, so as long as the spring still bottoms out before the fork i can add x amount of preload? Edited August 1, 2012 by 03machstock

[tribalbc]

Ah ok, now how much preload could i add before bottoming out. Correct me if im wrong but the spring bottoms out before the fork, so as long as the spring still bottoms out before the fork i can add x amount of preload?

I would go to the suspension forum for details of how much preload you should add but I would guess 5-10mm.

I don't see an issue with bottoming as your spring length remains the same, the spring is just slightly compressed. It used to be fairly common practise back in the day. Just might loose some initial plushness.

Cutting coils also raises spring rate. I'm sure some Guru in the suspension forum could come up with a good formula for you.

[03machstock]

I would go to the suspension forum for details of how much preload you should add but I would guess 5-10mm.

I don't see an issue with bottoming as your spring length remains the same, the spring is just slightly compressed. It used to be fairly common practise back in the day. Just might loose some initial plushness.

Cutting coils also raises spring rate. I'm sure some Guru in the suspension forum could come up with a good formula for you.

Ok thanks alot, the suspension guy said something about cutting coils when i called him today because as i left it yesterday i was going to do some research and try to find someone that had a pair of springs laying around. So perhaps i will go that route. Thanks for your ideas and the help.

[RhinofromWA]

No, they DO NOT make springs for this anymore. .48 is optimal for my weight. They used to make a .47 but it is obsolete and that was my closest option. If i could just get any brand springs close i would do that. I have already called racetech and they said im pretty much screwed.

So we know what spring rate you are looking for... what is the spring diameter and length you need? Once you know that I bet you will have better chance finding something.... who knows that same spring may being used in some other application. It is a fork spring.... probably not propriety. Worth a shot.

Edited August 2, 2012 by RhinofromWA

[03machstock]

So we know what spring rate you are looking for... what is the spring diameter and length you need? Once you know that I bet you will have better chance finding something.... who knows that same spring may being used in some other application. It is a fork spring.... probably not propriety. Worth a shot.

hmmm thats a good thought too, ill have to check into if i can find specs, and if not just pull a spring and measure it. I actually just talked to a company also that said if i gave them o.d. and free length and what rate i wanted they would make them for $175 a pair which worse come to worse i might have to do. Thanks

[CalRMX]

Are there RM250 springs that might work?

[03machstock]

Are there RM250 springs that might work?

From what i gathered so far, the 41mm kyb forks were only made for a couple years and weren't that popular, so no one makes aftermarket springs for it anymore. I'm pretty sure all the springs in those forks were close to being the same if not the same, and i am far from the weight range they handle. Right now i still have to pull the springs out and measure them as suggested.

[RhinofromWA]

From what i gathered so far, the 41mm kyb forks were only made for a couple years and weren't that popular, so no one makes aftermarket springs for it anymore. I'm pretty sure all the springs in those forks were close to being the same if not the same, and i am far from the weight range they handle. Right now i still have to pull the springs out and measure them as suggested.

The cool thing about forks is that there is no linkage involved... it is straight 1:1 ratio so if there are another fork with the same diameter/length/rate you need they should work. ?

.... and as you have found out, lots of places can make you a spring if that route is needed.

[03machstock]

Yea i know, iv just been dragging my feet, just got my rear shock back yesterday and i have to rebuild my linkage before i put that back on. Ill pull the forks after that so my bike is only half way apart at any given point haha.

[03machstock]

So i put the rear shock back in after I replaced all the linkage bearings and took it for a spin and wow what a difference. After that I put the old girl away and ripped the forks right off and took out the springs. Then I took some measurements and called up Cannon Racecraft and gave them the specs I need. They are going to make me a pair of front springs to match my freshly redone rear. After talking to the local suspension shop, this was my best option (as long as the make the springs to the right rate and they fit in my fork tubes haha) as cutting links and making up spacers would work to a certain extent, but he said we most likely wouldnt come close to the rate i need.